1. Field of the Invention
The present invention relates to display devices and liquid crystal display devices each including a plurality of pixels constituting a display screen. More specifically, the present invention relates to a multi-primary color display device which can be used for various displays such as a liquid crystal TV, a PDP (Plasma Display Panel), an organic EL (Electroluminescent), and a FED (Field Emission Display) by constituting an image with multi-primary colors.
2. Description of the Related Art
As display devices, various displays forming an image by pixels have been widely used as means for displaying information or images. Display devices in which one pixel is constituted by sub-pixels of three colors of red (R), green (G), and blue (B) as shown in FIG. 14 and thereby color display is provided are common, for example. In such a color display technology, it has been recently considered that a color reproduction range is enlarged for improvement in display quality. For example, color purity of three primary colors of RGB is increased, and thereby the color reproduction range is enlarged in a chromaticity diagram. In this case, however, reduction in brightness is generated.
In addition, it has been impossible in principle that a color other than the combination of these three primary colors is expressed. It is needed in order to express a color without the region formed by three tops in the CIE (Commission Internationale ed I'Eclairage) 1931 Chromaticity Diagram, that is, a color without RGB triangle, that the region of the RGB triangle is enlarged, or/and, a color without this triangle region is used. Additionally, a method of using a color within a (polygonal) region (for example, W) is mentioned as a method of compensating brightness with enlarging the color reproduction range.
A technology for enlarging the region in the chromaticity diagram by increasing the number of the primary colors to four, five, six, and the like, using a new color other than the three primary colors has been developed. See, for example, “SID sokuhou”, “online”, May 26, 2004, Nikkei Business Publications, Inc. “search on Aug. 18, 2004”, Internet URL:http://ne.nikkeibp.co.jp/members/NEWS/20040526/103584/ (Nonpatent Document 1). Another method discloses a liquid crystal display device in which each pixel of red, blue, green, and white is arranged in the row direction, and in the column direction, pixels with the same color are arranged, for example. See, for example, pages 1, 2, and 22 in Japanese Kokai Publication No. 2004-102292 (Patent Document 1). In this liquid crystal display device, a method of adding W to the RGB three primary colors, thereby improving the brightness and the color reproduction range is proposed. Two color arrays of stripe array and matrix array have been proposed. The stripe array is commonly adopted in application of large displays such as TV, because of matching property with images. FIG. 15 shows an embodiment of this stripe array in this liquid crystal display device. In this case, R, G, B, and W are arranged in this order to form one pixel. In such a multi-primary color display, design that is advantageous in terms of the color reproduction range can be permitted, and the color reproduction range is enlarged without increasing the color purity. Therefore, in this respect, the brightness is not reduced. However, the number of data increases depending on the division number only by dividing one pixel into the number of the primary colors, and the number of a data driver or an opening ratio is not enough. Therefore, in this respect, there is room for improvement. In addition, a liquid crystal display device in which a fine filter forming a color filter has four colors corresponding to a R-G axis and a B-Y axis is disclosed. See, for example, pages 1, 2, and 6 in Japanese Kokai Publication No. 2001-209047 (Patent Document 2). However, also in this liquid crystal display device, there is room for improvement for eliminating demerits associated with the multi-primary colors.
With respect to a liquid crystal display device performing color display using sub-pixels of at least four primary colors, it is disclosed that five primary colors of RGYBC are arranged as four sub-pixels of RGYB, CRGY, BCRG, YBCR, or GYBC. See, for example, pages 1, 2, and 9 in the Drawings of WO 02/101644 (Patent Document 3). However, in this liquid crystal display device, the five primary colors are simply arranged in the sub-pixels by rotation when display is provided by four sub-pixels using five primary colors of RGYBC. In such an arrangement pattern, reduction in effectual resolution or visual problems may be generated. A large screen display device comprising five different magnetic reversal elements for four color display and adopting a four-color combination of displayable colors among red, green, blue, white, and back is disclosed. See, for example, page 1 in Japanese Kokai Publication No. Hei-05-143005 (Patent Document 4). Also in this display device, any four colors among the five colors are combined, and improvement in display quality is need. Therefore, there is room for improvement in order to further enhance basic performances in displays such as a liquid crystal TV for which excellent display quality is needed with exhibiting properties such as high color reproduction range and high brightness.